The candidate for this K23 Career Development Award is a pediatric gastroenterologist who specializes in esophageal physiology. The candidate's long-term career goal is to have an academic research career in pediatric gastroenterology that improves the health of children through the study of reflux-related respiratory diseases. Short-term career goals to be achieved with this award include: (1) to obtain formal training in advanced statistics and epidemiology;(2) to gain additional expertise in the use of multi-channel intraluminal impedance (pH-MII), an emerging tool for measuring gastroesophageal reflux (GER);(3) to deepen the candidate's knowledge of the relationship between GER and respiratory disease;and (4) to acquire the valuable mentorship required to ensure the candidate's progress toward becoming a R01-funded clinical investigator. The candidate's primary mentor, Dr. David Christiani, has a strong background in pulmonology and epidemiology that forms the basis for his studies of the cause-and-effect relationships between toxins and respiratory disease. The candidate's multidisciplinary mentorship team also includes faculty members with expertise in pediatric pulmonology, otolaryngology, gastroenterology, and statistics. Training activities include coursework in advanced statistics and epidemiology;participation in clinical research conferences;and didactic instruction from mentors. This application outlines the first pediatric study to determine the role of non-acid reflux in respiratory disease using two novel technologies: pH-MII and esophageal manometry with impedance. Through cross-sectional and cohort studies of children, the candidate will determine (1) the temporal relationship between non-acid reflux and respiratory symptoms;(2) the strength of association and the dose-response relationship between non-acid reflux and markers of reflux-related respiratory disease;and (3) the strength of association and the dose-response relationship between non-acid reflux and the severity of respiratory disease. Findings from this research may lead to a paradigmatic shift from acid reflux to non-acid reflux as a cause of respiratory disease. Findings from this study also may lead to improved strategies for diagnosing and treating respiratory diseases, which already account for significant morbidity in children.